P139. Clinically relevant percent reduction (CRPR): a new definition of clinically significant change for lumbar spine surgery

Abstract

BACKGROUND CONTEXT Minimal clinically important difference (MCID) represents the smallest, clinically relevant change in a patient-reported outcome (PRO) score. However, the literature suggests that an absolute change from baseline may not be a reliable marker of response to treatment for patients with a low or high baseline PRO score. An alternative to MCID is a threshold of clinical relevance defined by percent reduction from baseline PRO score. PURPOSE The purpose of this study was to determine whether a clinically relevant percent reduction (CRPR) of 30% in disability and pain scores is a valid method for determining clinical improvement at 12 months after lumbar spine surgery. STUDY DESIGN/SETTING Retrospective evaluation of prospectively collected data from a national surgical spine registry, the Quality Outcomes Database (QOD). PATIENT SAMPLE A total of 23,280 participants undergoing elective surgery for a lumbar degenerative condition (primary stenosis, disc herniation, spondylolisthesis (Grade I) and symptomatic mechanical disc collapse or revision surgery for recurrent same-level disc herniation, pseudarthrosis and adjacent segment disease). OUTCOME MEASURES Outcomes were disability (ODI), back and leg pain (NRS-BP/LP), and satisfaction (NASS scale). METHODS Participants completed a preoperative assessment and follow-up assessment at 1-year. The change in ODI and NRS-BP/LP scores were categorized as met CRPR (percent change ≥30%) or not met CRPR (percent change RESULTS Results from the satisfaction prediction models found that the OR for 30% ODI CRPR was 11.1 (10.2 to 12.1) and for ODI MCID was 7.8 (7.2 to 8.4), while 30% NRS-BP and NRS-LP CRPR was 7.9 (7.3 to 8.5) and 6.7 (6.2 to 7.2) compared to MCID ORs of 5.5 (5.1 to 5.9) and 5.6 (5.2 to 6.0) (p CONCLUSIONS CRPR may be a more clinically relevant method for identifying response to treatment since it can be applied to broad spinal surgery populations and takes into account the baseline PRO score. Furthermore, a 30% CRPR appears to outperform established MCID thresholds for patients with either low or high preoperative disability and pain scores. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.